There are created and established two special funds to be known and designated as the "equipment rental funds," to be used as revolving funds to be expended for salaries, wages and operations required for the repair, replacement, purchase and operation of all self-propelled motor vehicles equipment, and all other equipment designated by the various department heads of the city of Aberdeen. The equipment rental funds shall include the purchase of all equipment, materials and supplies to be used in the administration and operation of each fund. One fund shall be termed "equipment rental operating fund" and the other shall be termed "equipment rental reserve fund."